Photosensitive apparatus



Jan. 7, 1941. w. x. BENDZ PHOTOSENSITIVE APPARATUS Filed Aug. 6, 1937 2 Sheets-Sheet l glg/ 0 Re .m Z wr N m M W WITNESSES:

ATTORN Y Jan. 7, 1941. w. l. BENDZ 2,227,483

PHOTOSENSITIVE APPARATUS Filed Aug. 6, 1937 2 Sheets-Sheet 2 0.9 /25'/ 07/727; g 23 an WITNESSES: fig INVENTOR W MMm/l BY W ATTORNEY Patented Jan. 7, 1941 UNITED STATES PATENT OFFICE PHOTOSENSITIVE APPARATUS Pennsylvania Application August 6, 1937, Serial No. 157,705

10 Claims.

My invention relates to photosensitive apparatus, and it has particular relation to apparatus for controlling the operation of a door.

It is an object of my invention to provide a simple and inexpensive operating device for a door that shall cause the door to open automatically when a person or object that is to move through the doorway is disposed in front of the door.

Another object of my invention is to provide a door actuating device that shall operate to open the door in response to the presence of a person or object in front of the door, to maintain the door open as the person or object moves through the doorway, and to reclose the door if the person or object moves back from the doorway or after passing through the doorway moves away from the door.

More specifically stated, it is an object of my invention to provide a photosensitive control system for a door that shall operate with certainty and that shall avoid the hazards to persons passing through the door which are involved in the usual automatic door control mechanisms.

According to my invention, I provide a control system comprising a pair of photosensitive devices connected in series. One of the photosensitive devices is energized by a beam of radiant energy projected along a path in front of the door, so that a person advancing towards the door intercepts the beam. The other photosensitive device is, when the door is closed, energized by an auxiliary source disposed adjacent thereto. When the door is open, the latter device is energized by a beam of radiant energy projected through the door in such away that one passing through the door would intercept the beam. When the door has been opened to such a position that the latter beam is transmitted through the doorway, the circuit of the auxiliary lamp is opened so that the second photosensitive device is controlled only by the beam of radiant energy transmitted through the doorway.

The photosensitive devices are connected in such manner that this condition of excitation controls the operation of the door actuating I mechanism. Normally with the door closed both of the photosensitive devices are energized; one by the beam projected in front of the door and the other by the auxiliary source disposed adjacent thereto. When a person intercepts the beam in front of the door, one of the photosensitive devices is deenergized and the door operating mechanism is actuated to cause the door to open. As the door opens sufficiently to permit the other beam of radiant energy to pass through the doorway, the auxiliary source is extinguished and the photosensitive network is then controlled by the beam in front of the door and the beam passing through the doorway. If the person who has intercepted the beam moves away from the door, it is reclosed by a spring. On the other hand, if the person passes into the doorway, he intercepts the beam of radiant energy passing through the doorway and causes the door to continue to open until he passes through.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Figure 1 is a view in perspective showing a portion of the door and the principal elements of the door operating and controlling mechanism;

Fig. 2 is a plan view partly in section showing the structure of the pneumatic cylinder utilized in operating the door;

Fig. 3 is a plan view showing the door in the open position;

Fig. 4 is a diagrammatic View showing the circuit arrangement for the control of the door operating mechanism;

Fig. 5 is a plan View showing a modification of one of the elements of my invention; and,

Fig. 6 is a plan view showing a modified door operating device.

The apparatus shown in Figs. 1 to 4 comprises a compressor 1 of any ordinary well known type (not shown in detail here because its structure 40 does not concern the present invention) which, when operating, transmits air under pressure through a tube 9 into a cylinder II. Within the cylinder II, a piston l3, connected through a rod 15, a slidable plate I1 and a system of levers 45 I9 and 2| to the door 23, is disposed. The compressor I and the cylinder I I and their associated elements are mounted on a bracket which is fastened to the wall 21 near the upper curves of the door; that is, above the hinges 29. The plate 5 ll slides between guides 3| in an auxiliary bracket 33 secured to the main bracket 25, and the lever 21 is secured to the door 23 adjacent to the hinge 29.

The piston I3 is located near the front end of 5;

the cylinder II when the door is closed and it is moved towards the rear of the cylinder when the compressed air is supplied carrying with it the rod i5 and the slide plate I l. The plate Il carries a pin near the center of which the lever I9 of the lever system is' pivotally secured at one end. The other end of the lever I9 and the free end of lever 2i are joined together by a movable pin 37 in such manner that the levers may pivot relative to each other. As the slide plate I! moves back under the action of piston rod [5, lever I9 moves back with it, at the same time pivoting about the pin 3'! and causing it to move back and carry with it the lever 2I and the door.

The cylinder II is provided with a valve 39 which permits any air under compression to leak out slowly. When the door is to close, the compressor I stops and the air is forced out of the valve 39 as the door closes under the action of a suitable spring II and the piston i3 moves towards the front portion of the cylinder II.

The operation of the compressor 1 is controlled in response to variations in the conducting condition of either one of a pair of photosensitive devices 53 and connected in series. The output of the series photosensitive network is amplified by a pair of controlled discharge devices 41 and 49 which may be of any ordinary type and, in the preferred practice of my invention, pentodes similar to the tubes sold by the Radio Corporation of America under the designation RCA-43.

While my invention may be operated from an alternating supply, the embodiment described herein is energized from a suitable direct-current potential supply, preferably of the order of 115 volts, which is represented in Fig. 4. by a pair of bus lines 5! and 53. The tubes 47 and 49 are of the indirectly heated type and their cathode heaters are connected directly across the source BI, 53 through a resistor 5'. and together with the resistor function substantially as 2. voltage divider. The anodes 59 of the tubes are con nected together and their common junction point 6! is connected to the positive conductor 51 of the supply through the exciting coil 53 of a relay 65. The emissive unipotential surfaces 6'! which operate as the cathodes of the tubes are also connected together, and their common junction point 69 is connected between the resistor 51 and the heaters 55, so that the potential supplied between the anodes 59 and the cathodes 61 is the potential drop across the resistors. The cathode ii of one of the photocells 43 of the photosensitive network is connected to the negative conductor 53 of the supply and its anode I3 is connected to the cathode II of the other photocell 45 of the network. The anode I3 of the last-mentioned photocell 45 is connected directly to the common junction point I5 of the control electrodes ll of the tube 4'! and 49. The junction point I5 is connected to the cathodes 61 of the tubes through a second resistor 19. The photosensitive network is thus supplied with potential from the main supply through the two resistors I9 and 51.

The two photosensitive devices 43 and 45 are disposed in a container 8| provided with a partition 83 for shielding them from each other and with openings 85 and 8'! through which beams of radiant energy may be projected onto the respective cathodes. The amplifier tubes 4'! and 49 and their associated elementes are disposed in a second container 89 mounted adjacent to the photocell container 8I so that only short connecting leads are necessary between the photosensitive devices 43 and 45 and the amplifiers.

The two containers BI and 89 are disposed in front of the door 23 and on one side of the doorway. On the other side of the doorway and also in front of the door a source 9I of radiant energy is mounted within a suitable container 93 in such manner that a beam 95 of radiant energy is projected from the source 9! to one of the photosensitive devices 43 through the corresponding opening 85 in the photocell container 8I. The photocell container BI and the source are both mounted at such heights above the fioor that the beam would be interrupted by any person or object which is to move through the door 28. A second source 9! of radiant energy is provided within a container 99 which is disposed on the opposite side of the door 23 and on the same side of the doorway as the first source, so that when the door is open a beam IllI of radiant energy from the second source would be projected through the open doorway. The second source 97 is so arranged that the radiant energy beam emitted by it when the door 23 is open, passes through the doorway and impinges on the other photosensitive device 45 through the corresponding opening 81 in the container 8I.

It is to be noted that if only the two sources SI and 91 were utilized, one of the photosensitive devices 45 would be deenergized with the door closed, and this is, of course, equivalent to an open circuit in the photosensitive network. Hence with the door closed the effect produced. would be the same as if a person or object were interrupting the beam of light from the first source. To avoid the difficulty involved in such an arrangement, an auxiliary source I93 of radiant energy is provided for maintaining the second photosensitive device 45 energized while the door is closed. The latter source may be disposed in the same portion I05 of the container 8I as the photosensitive device 45 and may project its radiaitons directly onto the latter photosensitive device.

Energy is supplied to the radiant energy sources 9|, 9'! and I03 from the main supply. The two main sources 9| and 91 are connected directly across the supply conductors 5| and 53. The auxiliary source I93 is connected across the supply conductors through the fixed contacts I01 of a switch I09, the movable contactor I II of which is adapted to be engaged and disengaged from the fixed contacts in accordance with the operation of the door 23. To provide for the operation of the movable contactor III, a cam surface H3 consisting of a narrow strip of sheet metal bent into proper shape is secured to the pin 35 mounted in the slider plate I! that is actuated by the piston rod I5. When the door 23 is in the closed position, the cam surface engages a roller I15 connected to the movable contactor III of the switch I01 and raises this contactor into engagement with the fixed contacts IO'I against the action of a spring I II. As the door opens, the roller II5 rides along the cam surface, maintaining the movable contactor III in engagement with the fixed contacts I01 until the opening in the door is such that the radiant energy beam IIiI from the second source 91 is projected onto the corresponding photosensitive device 45, At this point an inclined portion H9 is provided in the cam surface H3 and the roller and the movable contactor together drop under the action of the spring II'l opening the circuit of the auxiliary source I03.

The compressor 1 is also connected across the supply conductors SI and 53,-but its connection is through the fixed contacts I2I of the relay 65 and it is, therefore, energized only when the relay 65 is energized and the movable contacts I23 of the relay engages the fixed contacts I2I. With the door closed, both photocells 43 and 45 of the network are energized. Under such circumstances, the current supplied by the parallel tubes 41 and 49 is relatively small, the relay 65 in their anode-cathode circuit is deenergized and its movable contactor I23 is disengaged from the corresponding fixed contacts I2I to maintain the compressor I deenergized. When a person or object interrupts the beam 95 of radiant energy projected in front of the door 23, the corresponding photocell '43 is deenergized and-the current flow throughtheparallel tubes 41 and 49 is increased to such an extent that the relay 65 is energized and closes the circuit through the compressor 1. Air is supplied to the cylinder and the door now begins to swing open. As it moves, the auxiliary source I03 is deenergized at the same time that radiant beam IIII from the main source 91 is projected onto the second photosensitive device 45. At this point, both. photocells are again energized and the compressor 1 is deenergized. However, if the person continues'through the door, the beam IOI of radiant energy projected through the open doorway is interrupted and the compressor I continues to supply air to the cylinder I I and thus the door is opened completely so that the person may pass through it. When the person has passed through the door, the compressor 1 is again deenergized, and as the compressed air leaks out through the valve 39, the door closes under the action of the spring 4|. If the person should move back from the door instead of continuing through the door when it first begins to open, the compressor I would also be deenergized and as whatever air has been forced into the cylinder leaks out through the valve 39, the door would close.

My invention has been described hereinabove as applied to a particular system. A number of modifications may be made in the system without departing from the scope of my invention. ,For example, in lieu of utilizing the cam switch arrangement for controlling the energization of the auxiliary source I93, a limit switch to be actuated by the door itself as it opens may be utilized.

The modified structure is shown in Fig. 5. The door engages a roller I25 mounted on one arm I 21 of an angular bar I29 pivoted at the center I3I. The other arm I33 of the bar carries a movable contact I35 which is engaged with 9. corresponding fixed contact I31 when the door is closed and is disengaged therefrom when the door, on opening, engages the roller I25 and pivots the angular bar I29. The fixed and movable contacts I35 and I3'I are, of course, connected to open and close the circuit of the auxiliary source 91.

In lieu of a pneumatic arrangement for operating the door, a purely electro-mechanical arrangement may be utilized. This is illustrated in Fig. 6 in which the door 23 is shown as pivoted by the rotation of a worm wheel I39 that engages a worm I4I rotated by a motor I43. The motor circuit is, of course, identical to the compressor circuit in the principal embodiment of my invention. It should be noted however that to close the door after it has been opened, the motor I43 is reversed and to properly connect the motor winding in each case for this purpose, the relay 65 is provided with two sets of contacts.

Where the repeated starting and stopping of the compressor 1 is undesirable because of the excessive wear, the compressor may be operated continuously to supply an air reservoir which is provided with a valve actuated by relay 65. The Q valve controls the supply of air to pipe 9.

As regards the sources of radiant energy which may be utilized, they may be of any general type which would be interrupted by the presence of a person or object in their path. Under ordinary circumstances visible, infra-red, or ultra-violet light may be utilized. It may happen, however, that the object for which the door is to open may conveniently interrupt a short or a long wave radio beam or very short wave radiant energy such as X-rays or y-rays. Where such radiation may be utilized, it, is intended that if my invention is otherwise applied, the system shall fall within the scope thereof. It is to be noted that if a short wave-length or a long wave-length radio wave is utilized, the photosensitive devices should be replaced by a corresponding pair of tuned receivers.

Finally, it is to be noted that my invention is in no way limited by the character of the door and the manner in which it opens. Specifically, my invention has been shown as applied to a door which swings about a pivot on one side of the doorway. My invention is also applicable to two-part doors, the parts of which swing about pivots on both sides of the doorway, to doors which open by sliding into the supports, or by sliding up or down.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. Apparatus for controlling the operation of a door comprising a mechanism for causing the door to open when closed, a first and a second photosensitive device connected in series circuit relation, means for so connecting said photosensitive devices to said mechanism that said mechanism is actuated to causethe door to open when either of said devices is deenergized, a firstsource of radiant energy for energizing said first photosensitive device, said source being so disposed that the radiant energy beam from it to the first photosensitive device is independent of the position of said door, a second-source of radiant energy for energizing said second photosensitive device, said second source being so disposed the radiant energy beam from it to said second device is interrupted when said door is closed and additional means for maintaining said second photosensitive device energized when said door is closed.

2. In combination a plurality of photosensitive devices, electrically connected in series, means to be actuated when only one of said devices is deenergized, means for projecting beams of radiant energy on each of said photosensitive devices and means for energizing one of said photosensitive devices when the beam projected thereon is intercepted by said means to be actuated, said means for energizing being inactive to energize said one device when the last said beam is intercepted in another way.

3. In combination, a first and a second photosensitive device of the emissive type connected in series, movable means to be actuated when only one of said devices is deenergized, means for projecting beams of radiant energy on said photosaid photosensitive devices when the beam projected thereon is intercepted by said movable .means, said energizing means being inactive to energize saidone device when the lastsaid beam is effective to energize said one device.

4. ,In combination, a pair of photoemissive devices connected in series circuit relation, means for projecting a beam of radiant energy on each of said devices, means for intercepting one of said beams, means for energizing the photoemissive device on which said beam is projected when said beam is intercepted by said intercepting means and means to be actuated by said intercepting means when it is not intercepting said beam to render said energizing means inactive.

.5. Apparatus for controlling the operation of a. door comprising a mechanism for causing the door to operate photosensitive means of the photoemissive type connected in series for controlling the actuation of said mechanism, a pair of beams of radiant energy for energizing said photosensitive means, one of said beams passing in front of said door in its closed position and the other passing through the doorway at an angle to the door when closed and additional means to be actuated by said door for maintaining said photosensitive means energized when said door is in a predetermined position.

6. Apparatus for controlling the operation of a door comprising a mechanism for causing the door to open when closed, a first and a second photosensitive device connected in series'circuit relation, means for so connecting said photosensitive devices to said mechanism that said mechanism is actuated to cause the door to open when either of said devices is deenergized, a first source of radiant energy for energizing said first photosensitive device, said source being so disposed that the radiant energy beam from it to the first photosensitive device is independent of the position of said door, a second source of radiant energy for energizing said second photosensitive device, said second source being so disposed the radiant energy beam from it to said second device is interrupted when said door is closed and additional means to be actuated by said door for maintaining said second photosensitive device energized when said door is closed.

'7. Apparatus for controlling the operation of a door comprising a mechanism for causing the door to open when closed, a first photosensitive device, a second photosensitive device, said devices being of the photoemissive type connected in series circuit relation, means for so connecting said photosensitive devices to said mechanism that said mechanism is actuated to cause the door to open when either of said devices is deenergized, a first source of radiant energy for energizing said first photosensitive device, said source being so disposed that the radiant energy beam from it to the first photosensitive device is sensitive devices and means for energizing one of independent of the position of said door, a second source of radiant, energy for energizing said second, photosensitive device, said second source beingso disposed the radiant energy beam from it to said second device is interrupted when said door is closed, a third source of radiant energy for energizing said second photosensitive device and means to be actuated by the door for energizing ,said third source when said door is closed beyond a given angle and for deenergizing said third source when said door is open beyond said angle.

8.'In combination with a pair of relatively movable objects and a motor-mechanism to produce relative motion between them, a control circuit for said motor-mechanism embodying a pair .of serially-connected photoelectric cells of the photoemissive type, means for illuminating both photoelectric cells when said pair of movable ob .jects are in one relative position, means actuated said mechanism embodying a pair of seriallyconnected photoelectric cells of the photoemissive type, means for illuminating both photoelectric cells when said movable object is within a predetermined region, means actuated by a predetermined movement of said object to cut oil the illumination from one of said cells and a second illuminating means arranged to illuminate said one photoelectric cell when the illumination thereof by said first illuminating means has been interrupted.

l0. Apparatus for controlling the operation of a movable object comprising a motor-mechanism for causing the said object to move, a first and a second photosensitive device connected in series circuit relation, means for so connecting said photosensitive devices to said mechanism that said mechanism is-actuated to cause the said object to move when either of said devices is deenergized, a first source of radiant energy for energizingsaid first photosensitive device, said source being so disposed that the radiant energy beam from it to the first photosensitive device is independent of the position of said movable ob- -ject, a second source of radiant energy for energizing said second photosensitive device, said second source being so disposed the radiant energy beam from it to said second device is interrupted when said movable object is in a predetermined'position and additional means for maintaining said second photosensitive device energized when said movable object is in the predetermined position.

' WALDEMAR I. BENDZ. 

